8/9/2019 Qualitative Analysis Intro
1/16
Experiment 9
Groups 9, 10, 11
8/9/2019 Qualitative Analysis Intro
2/16
` Qualitative inorganic analysis is the part
of analytical chemistry which seeks to
establish elemental composition of
inorganic compounds by using various
reagents.
8/9/2019 Qualitative Analysis Intro
3/16
` It is mainly focused on detecting ions in an
aqueous solution, so materials in other
forms need to be brought into this state
before using standard methods.` The aqueous solution is then treated with
various reagents to test for reactions
characteristic of certain ions which result
in color change, solid formation, etc.
8/9/2019 Qualitative Analysis Intro
4/16
` Ions are removed in groups from the initial
aqueous solution. After each group has
been separated, then testing is conducted
for the individual ions in each group.
8/9/2019 Qualitative Analysis Intro
5/16
` Analytical chemistry is a category of chemistry
with a broad mission of understanding the
chemical composition of all matter and developing
the tools and experiments to make qualitative orquantitative measurements.
` 2 Types:
a. Qualitative Analysis
b. Quantitative Analysis
8/9/2019 Qualitative Analysis Intro
6/16
` Traditionally, it was concerned with what
chemicals are present, what their characteristics
are, and in what quantities they are present
` These questions are often involved in questionsmore dynamic such as what chemical reaction an
enzyme catalyzes or how fast it does it, or even
more dynamic such as what is the transition state
of the reaction
8/9/2019 Qualitative Analysis Intro
7/16
` Solubility test
` Centrifugation
`
Decantation` Flame test
8/9/2019 Qualitative Analysis Intro
8/16
` This procedure is employed using both dilute and
concentrated forms of HCl, HNO3, H2SO4, and
aqua regia. (In Expt. 9, 6M HCl, 6M HNO3,
concentrated HCl and HNO3, and aqua regia)` In most cases, HCl is the preferred acid, although
HNO3 is used to dissolve many metallic minerals
containing lead and silver.
`
Water is used before the acids to determinesolubility.
8/9/2019 Qualitative Analysis Intro
9/16
` A centrifuge is a piece of equipment that
puts an object in rotation around a fixed
axis, applying a force perpendicular to the
axis.
` The centrifuge works using the sedimentation
principle, where centripetal acceleration is usedto evenly distribute substances (usually present
in a solution for small scale applications) of
greater and lesser density
` Lab centrifuge: no physical separation
between the solid and liquid phase butaccelerated settling due to centrifugal
acceleration.
8/9/2019 Qualitative Analysis Intro
10/16
` Decantation is a process for separating some
mixtures by carefully pouring the solution from a
container so that the precipitate is left in the bottom
of the original container.` Usually some of the solution must be left in the
container, and care must be taken to prevent a
small amount of precipitate from flowing with the
solution out of the container. It's generally used to
separate a liquid from an insoluble solid.
8/9/2019 Qualitative Analysis Intro
11/16
` The flame test is a
procedure used to detect
the presence of metal ions
by introducing a sample of
the element or compound
to a hot, non-luminous
flame, and observing the
color that results.
Samples are usually held on aplatinum wire cleaned repeatedly
with hydrochloric acid to remove
traces of previous analytes.
8/9/2019 Qualitative Analysis Intro
12/16
Symbol Name Color As Arsenic Blue
B Boron Bright green
Ba Barium Pale/Apple green
Ca Calcium Brick red
Cs Cesium BlueCu(I) Copper(I) Blue
Cu(II) Copper(II) (non-halide) Green
Cu(II) Copper(II) (halide) Blue-green
Fe Iron Gold
In Indium Blue
K Potassium Lilac
Li Lithium Red
Mg Magnesium White
Flame test chart part 1
8/9/2019 Qualitative Analysis Intro
13/16
Symbol Name Color
Mn(II) Manganese(II) Yellowish green
Mo Molybdenum Yellowish green
Na Sodium Intense yellow
P Phosphorus Pale bluish green
Pb Lead Blue
Rb Rubidium Red-violet
Sb Antimony Pale green
Se Selenium Azure blue
Sr Strontium Crimson
Te Tellurium Pale green
Tl Thallium Pure green
Zn Zinc Bluish green
Flame test chart part 2
8/9/2019 Qualitative Analysis Intro
14/16
` To identify the cations present in a given liquid
sample
` To identify the cation and the anion in a given
sample of a salt` To write the name and correct formula of the salt
8/9/2019 Qualitative Analysis Intro
15/16
` After solubility test, dissolve a pinch of sample in
the appropriate solution and use the resulting
solution as the cation test solution
8/9/2019 Qualitative Analysis Intro
16/16
General Assaying Procedures
http://www.thegeozone.com/members/assay/assay04.jsp#solubility
Wikipedia, The Free Encyclopedia
http://en.wikipedia.org/wiki/Main_Page